Spam and Pieces
One thing that web is full of will be people who could care less if they are classified as spam or authentic users. These people have something else in mind. Outside providing havoc to your site, they are trying to market their own sites which are totally undefined.
They love to prey on beginners. Just when you think you are doing a good job in building your site, you will find some who are up to no good. Moderating them is great but be sure you know which are spam and which are not. It is really simple. If you spot some URL’s, normally it is a sign that they are spam comments. But be sure to read them to make sure that they are not sane ones.